Rather than switching from one size to another (which doesn't provide any more flexibility than we already have), 23292.diff​ adds a filter to $attachment_url. More flexibility for different use cases.

If images don't have medium sizes, or if the medium size is configured oddly (such as 0 x 0, to kill the size), then full will get used. The default dimensions for thumbnails are simply too small for the new UI.

I think there are some good ideas here for a future release. It is not a pressing issue at this point.

What exactly is a "medium size" image? I've got an image that has sizes 90x90, 150x150, 158x158, 300x300, 370x370, 900x900, and 1024x1024. And the full size (2262x2261). And yet when I click "Add Media," it still uses the full 2262x2261 as the thumbnail. Doesn't make any sense.

I dunno if I'd call this "not a pressing issue." For e-commerce store owners who have large images, I think it is. This runs up the CPU usage and makes the computer run HOT. I think at least some sort of interim patch would be nice for 3.5.x.

What exactly is a "medium size" image? I've got an image that has sizes 90x90, 150x150, 158x158, 300x300, 370x370, 900x900, and 1024x1024. And the full size (2262x2261). And yet when I click "Add Media," it still uses the full 2262x2261 as the thumbnail. Doesn't make any sense.

I dunno if I'd call this "not a pressing issue." For e-commerce store owners who have large images, I think it is. This runs up the CPU usage and makes the computer run HOT. I think at least some sort of interim patch would be nice for 3.5.x.

Yep, all these file size variations are within the same folder in wp-content/uploads/2013/07. I believe WooCommerce generated these, as these are the various file sizes set there (150, 370, 90, 140, and 900 anyway). I also tried "regenerate thumbnails" plugin, that didn't help.

ocean90: Didn't see anything relevant in wp-admin/options-media.php.

Ok, this is helpful. As a test, I copied one of these large images and uploaded to my own WP site which doesn't have WooCommerce or a lot of plugins going on. And when clicking "Add Media" on a post, the image used is actually 300x300. So it's properly using a thumbnail, not a full size. Any ideas why my wife's WooCommerce site would not be behaving this way?

If images don't have medium sizes, or if the medium size is configured oddly (such as 0 x 0, to kill the size), then full will get used. The default dimensions for thumbnails are simply too small for the new UI.

Maybe I'm missing something, but the default thumbnail is 150 x 150, and the default medium is 300 x 300, yet it looks like the divs these medium size images sit in all have max-height and width set to 120 from media-views.css?

I just watched my co-worker's computer almost melt from loading hundreds of hi-res images at once. This is due to an unbounded wp.media.query - loading 100s of hi-res images squished as thumbnails is pretty absurd.

When you load the modal (and you have 100s of attachments), it requests page 2 immediately after page 1, so 80 items load at once. If your full-size images are 4MB, this is loading 320MB of images at once.

If you have 100s of images, "Uploaded to this post" is a much saner default mode.

I'd like to see us only take special cases when we're not loading thumbnails. It might not be easy to determine, but since it's pretty edge, I'd like to not hide the library whenever anyone has more than 40 images.

We also have the upload/browse state, in terms of which one should be uploaded first. (It's supposed to remember the user's preference, though it has a bit of a glitch I think.) We could also just as easily remember if the user wants "Uploaded to this post" consistently as well.

There are a lot of minor issues here that turn into a mess when combined. Let's see what we can fix in 4.0.

This makes the medium and large image sizes the same as the thumbnail. Because the image sizes are all the same only one size is saved to disk. The media manager now uses the size of the image set for thumbnail.